Camera module and method for assembling same

ABSTRACT

The present invention provides a method for assembling a camera module, including: arranging a first sub-lens assembly and a photosensitive assembly on an optical axis of a second sub-lens assembly to form an optical system capable of imaging; increasing an actual measured resolution of imaging of the optical system to a first threshold by adjusting a relative position of the first sub-lens assembly with respect to the second sub-lens assembly; decreasing an actual measured image plane inclination of imaging of the optical system, obtained by using the photosensitive element, to a second threshold by adjusting an angle of an axis of the photosensitive assembly with respect to a central axis of the second sub-lens assembly; and connecting the first sub-lens assembly, the second sub-lens assembly, and the photosensitive assembly. The present invention further provides a corresponding camera module.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Chineseapplication No. 201710814255.5, filed on Sep. 11, 2017 in the StateIntellectual Property Office of China, the disclosure of which isincorporated herein in its entirety by reference.

TECHNICAL FIELD

The present invention relates to the field of optical technologies, andspecifically to a camera module solution.

BACKGROUND

With the spread of mobile electronic devices, technologies related tocamera modules applied to mobile electronic devices to help users withimaging (for example, capturing a video or an image) have developedrapidly. In recent years, camera modules have been widely applied invarious fields such as health care, security protection, and industrialproduction.

To meet the increasingly extensive market demands, high resolution,small size, and large aperture are the irreversible trend of cameramodule development. The requirements of the market on the imagingquality of camera modules are becoming higher. Factors affecting theresolution of a camera module of a given optical design include thequality of an optical imaging lens assembly and the manufacturingdeviations introduced in the module packaging process.

Specifically, during the manufacturing process of the optical imaginglens assembly, factors affecting the resolution of the lens assemblyinclude material and assembly deviations of various parts, deviations inthickness of lens spacer elements, assembly deviations of the lenses,the change in the refractive index of the lens material, and so on. Thematerial and assembly deviations of various parts include the opticalsurface thickness of each individual lens, the optical surface rise ofthe lens, the optical surface form, the radius of curvature,eccentricity of the lens surface and eccentricity between the lenssurface, the optical surface inclination of the lens, and so on. Thevalues of such deviations depend on the mold precision and the moldingprecision control capability. The deviations in thickness of lens spacerelements depend on the machining precision of the elements. The assemblydeviations of the lenses depend on the dimensional tolerances of theelements assembled and the assembly precision of the lens assembly. Thedeviations caused by the change in the refractive index of the lensmaterial depends on the stability of the material and the batchconsistency.

The deviations of the elements affecting the resolution may manifest asan accumulative deterioration, and the accumulative deviation increasesas the number of lenses increases. In existing resolution solutions,dimensional tolerances of elements with high sensitivity are controlled,and lens rotation is performed to increase the resolution. However,because a high-resolution, large-aperture lens assembly is sensitive andhas strict tolerance requirements, for example, 1 μm lens eccentricityleads to 9′ image plane inclination in some sensitive lens assemblies,the difficulty in lens machining and assembling increases. In addition,because the feedback period is long in the assembly process, thecapability of process index (CPK) of the lens assembly is low andfluctuates greatly, leading to a high failure rate. Moreover, asdescribed above, there are numerous factors affecting the resolution ofthe lens assembly, and such factors exist in various elements. Becausethe control of such factors is limited by the manufacturing precision,simply improving the precision of the elements only provides a limitedeffect, requires high costs, and cannot meet the increasingly highrequirements of the market on the imaging quality.

On the other hand, in the machining process of the camera module, theassembly process of each structural part (for example, photosensitivechip mounting, motor lens assembly locking) may lead to an inclinationof the photosensitive chip, and the resolution of the imaging module maybe unable to reach the given specification due to the accumulation ofmultiple inclinations, resulting in a low yield in the module factory.In recent years, in the module factory, when the imaging lens assemblyand the photosensitive module are assembled, an active alignment processis used to compensate for the inclination of the photosensitive chip.However, the compensation ability of such process is limited. Becausemultiple aberrations affecting the resolution are originated from theability of the optical system itself, the existing active alignmentprocess for the photosensitive module cannot compensate for theinsufficient resolution of the optical imaging lens assembly.

SUMMARY

The present invention is to provide a solution that can overcome atleast one of the defects of the prior art.

According to an aspect of the present invention, there is provided amethod for assembling a camera module, comprising: preparing a firstsub-lens assembly, a second sub-lens assembly, and a photosensitiveassembly, wherein the first sub-lens assembly comprises a first lensbarrel and at least one first lens, the second sub-lens assemblycomprises a second lens barrel and at least one second lens, and thephotosensitive assembly comprises a photosensitive element; arrangingthe first sub-lens assembly and the photosensitive assembly on anoptical axis of the second sub-lens assembly, to form an optical systemcapable of imaging and comprising the at least one first lens and the atleast one second lens; increasing actual measured resolution of imagingof the optical system to a first threshold by adjusting a relativeposition of the first sub-lens assembly with respect to the secondsub-lens assembly; decreasing an actual measured image plane inclinationof imaging of the optical system, obtained by using the photosensitiveelement, to a second threshold by adjusting an angle of an axis of thephotosensitive assembly with respect to a central axis of the secondsub-lens assembly; and connecting the first sub-lens assembly and thesecond sub-lens assembly, so that the relative position of the firstsub-lens assembly and the second sub-lens assembly remain unchanged; andconnecting the photosensitive assembly and the second sub-lens assembly,so that the angle of the axis of the photosensitive assembly withrespect to the central axis of the second sub-lens assembly remainsunchanged.

In the increasing actual measured imaging resolution of the opticalsystem to the first threshold, the adjusting the relative positioncomprises: increasing the actual measured resolution of imaging of theoptical system by moving the first sub-lens assembly with respect to thesecond sub-lens assembly in an adjustment plane.

In the increasing actual measured resolution of imaging of the opticalsystem to the first threshold, the movement in the adjustment planecomprises translation and/or rotation in the adjustment plane.

The decreasing the actual measured image plane inclination of imaging ofthe optical system, obtained by using the photosensitive element, to asecond threshold is performed after the increasing actual measuredresolution of imaging of the optical system to the first threshold.

In the decreasing the actual measured image plane inclination of imagingof the optical system, obtained by using the photosensitive element, tothe second threshold, obtaining the actual measured image planeinclination comprises: setting a plurality of targets corresponding todifferent test points in a test area/field of view; and acquiring aresolution defocusing curve corresponding to each test point based on animage output by the photosensitive assembly.

In the decreasing the actual measured image plane inclination of imagingof the optical system, obtained by using the photosensitive element, toa second threshold, the decreasing the actual measured image planeinclination to the second threshold is: decreasing a position offset inthe optical axis direction between peaks of the resolution defocusingcurves corresponding to the different test points in the test area/fieldof view to the second threshold.

The increasing actual measured resolution of imaging of the opticalsystem to the first threshold comprises:

increasing actual measured resolution of imaging of the optical systemin a reference area/field of view to a corresponding threshold by movingthe first sub-lens assembly with respect to the second sub-lens assemblyin an adjustment plane; and then increasing actual measured resolutionof imaging of the optical system in a test area/field of view to acorresponding threshold by tilting a central axis of the first sub-lensassembly with respect to a central axis of the second sub-lens assembly.

In the increasing actual measured resolution of imaging of the opticalsystem to the first threshold, obtaining the actual measured resolutionof imaging of the optical system comprises: setting a plurality oftargets corresponding to different test points in the referencearea/field of view and the test area/field of view; and acquiring aresolution defocusing curve corresponding to each test point based on animage output by the photosensitive assembly.

In the increasing actual measured resolution of imaging of the opticalsystem in the reference area/field of view to the correspondingthreshold, the increasing the actual measured resolution to thecorresponding threshold comprises: increasing a peak of a resolutiondefocusing curve corresponding to imaging of a target of a test point inthe reference area/field of view to the corresponding threshold.

In the increasing actual measured resolution of imaging of the opticalsystem in the test area/field of view to the corresponding threshold,the increasing the actual measured resolution to the correspondingthreshold comprises: increasing a smallest one of peaks of resolutiondefocusing curves corresponding to imaging of a plurality of targets inthe test area/field of view to the corresponding threshold.

The increasing actual measured resolution of imaging of the opticalsystem to the first threshold further comprises: matching an actualmeasured image plane of imaging of the optical system obtained accordingto an image output by the photosensitive element with a target surfaceby moving the first sub-lens assembly with respect to the secondsub-lens assembly along the optical axis.

In the increasing actual measured resolution of imaging of the opticalsystem to the first threshold, the first sub-lens assembly is moved withrespect to the second sub-lens assembly within a first range in anadjustment plane; and in the decreasing the actual measured image planeinclination of imaging of the optical system, obtained by using thephotosensitive element, to a second threshold, if the actual measuredimage plane inclination cannot reach the second threshold, areadjustment step is further performed until the actual measured imageplane inclination is decreased to the second threshold.

The readjustment step comprises: moving the first sub-lens assembly withrespect to the second sub-lens assembly within a second range in theadjustment plane, wherein the second range is smaller than the firstrange; and adjusting an angle of the axis of the photosensitive assemblywith respect to the optical axis, so as to decrease the actual measuredimage plane inclination of imaging of the optical system obtained byusing the photosensitive element.

In the connecting step, the first sub-lens assembly and the secondsub-lens assembly are connected by a bonding or welding process.

In the connecting step, the photosensitive assembly and the secondsub-lens assembly are connected by a bonding or welding process.

The welding process comprises laser welding or ultrasonic welding.

According to another aspect of the present invention, there is furtherprovided a camera module, comprising: a first sub-lens assembly,comprising a first lens barrel and at least one first lens; a secondsub-lens assembly, comprising a second lens barrel and at least onesecond lens; and a photosensitive assembly, comprising a photosensitiveelement, wherein the first sub-lens assembly and the photosensitiveassembly are arranged on an optical axis of the second sub-lens assemblyto form an optical system capable of imaging and comprising the at leastone first lens and the at least one second lens; the first sub-lensassembly and the second sub-lens assembly are fixed together by a firstconnecting medium; and the second sub-lens assembly and thephotosensitive assembly are fixed together by a second connectingmedium, wherein the second connecting medium is adapted to cause acentral axis of the second sub-lens assembly to have a second angle ofinclination with respect to an axis of the photosensitive assembly.

The first connecting medium is adapted to prevent the first sub-lensassembly and the second sub-lens assembly from abutting against eachother.

The first connecting medium is further adapted to cause a central axisof the first sub-lens assembly to have a first angle of inclination withrespect to the central axis of the second sub-lens assembly.

The first connecting medium is further adapted to cause a central axisof the first sub-lens assembly to be staggered with respect to thecentral axis of the second sub-lens assembly.

The first connecting medium is further adapted to cause the firstsub-lens assembly and the second sub-lens assembly to have a structuralclearance therebetween.

The first connecting medium is a bonding medium or a welding medium, andthe second connecting medium is a bonding medium or a welding medium.

A central axis of the first sub-lens assembly is staggered with respectto the central axis of the second sub-lens assembly by 0 to 15 μm.

A central axis of the first sub-lens assembly has an angle ofinclination of smaller than 0.5° with respect to the central axis of thesecond sub-lens assembly.

The central axis of the second sub-lens assembly has an angle ofinclination of smaller than 1° with respect to the axis of thephotosensitive assembly.

The first connecting medium is further adapted to cause a relativeposition of the first sub-lens assembly and the second sub-lens assemblyto remain unchanged, and the relative position cause actual measuredresolution of imaging of the optical system to be increased to a firstthreshold; and

the second connecting medium is further adapted to cause an actualmeasured image plane inclination of imaging of the optical system,obtained by using the photosensitive element, to be decreased to asecond threshold.

The second sub-lens assembly further comprises a motor, the motorcomprises a motor base, the photosensitive assembly is connected to themotor base by the second connecting medium; and the actual measuredresolution is a obtained when the motor is in on state, and the actualmeasured image plane inclination is obtained when the motor is in onstate.

Compared with the prior art, the present invention has at least one ofthe following technical effects.

In the present invention, the resolution of the camera module can beimproved.

In the present invention, the capability of process index (CPK) of massproduction of the camera module can be improved.

In the present invention, the requirements on the material precision andassembly precision of various elements of the optical imaging lensassembly and module can be lowered, and the overall costs of the opticalimaging lens assembly and module can be reduced.

In the present invention, a real-time adjustment of various aberrationsof the camera module can be implemented during the assembly process, soas to reduce the failure rate and the production costs, and improve theimaging quality.

In the present invention, the relative position of the first sub-lensassembly and the second sub-lens assembly can be adjusted over multipledegrees of freedom during the assembly process to improve theresolution, and the image plane inclination caused by the adjustment ofthe relative position of the first sub-lens assembly and the secondsub-lens assembly can be compensated for by adjusting the relativeinclination between the photosensitive assembly and the second sub-lensassembly, thereby better improving the imaging quality.

In the present invention, because the image plane inclination can becompensated for by adjusting the relative inclination between thephotosensitive assembly and the second sub-lens assembly, the influenceof the adjustment of relative position on the image plane inclinationdoes not need to be considered or does not need to be considered toomuch during the adjustment of the relative position of the firstsub-lens assembly and the second sub-lens assembly, so that the processdifficulty in adjusting the relative position of the first sub-lensassembly and the second sub-lens assembly is reduced, thereby improvingthe assembly efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are shown in the accompanying drawings. Theembodiments and accompanying drawings disclosed herein are provided forthe purpose of description, and should not be construed as limiting.

FIG. 1 is a flow chart of a method for assembling a camera moduleaccording to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a first sub-lens assembly, asecond sub-lens assembly, a photosensitive assembly and their initialpositions according to an embodiment of the present invention.

FIG. 3 illustrates a relative position adjustment method according to anembodiment of the present invention.

FIG. 4 illustrates a rotational adjustment according to anotherembodiment of the present invention.

FIG. 5 illustrates a relative position adjustment method furtherallowing for adjustment in directions v and w according to still anotherembodiment of the present invention.

FIG. 6 illustrates MTF defocusing curves in an initial state accordingto an embodiment of the present invention.

FIG. 7 illustrates MTF defocusing curves after adjustment in step 300according to an embodiment of the present invention.

FIG. 8 illustrates the first sub-lens assembly, the second sub-lensassembly, and the photosensitive assembly and a positional relationshipthereof after the relative position of the first sub-lens assembly andthe second sub-lens assembly are adjusted according to an embodiment ofthe present invention.

FIG. 9 is a schematic principle diagram of an image plane inclination.

FIG. 10 is a schematic diagram of comparison of images at a centralposition, a periphery 1, and a periphery 1′.

FIG. 11 illustrates MTF defocusing curves after adjustment in step 400according to an embodiment of the present invention.

FIG. 12 illustrates the first sub-lens assembly, the second sub-lensassembly, and the photosensitive assembly and a positional relationshipthereof after the relative inclination between the photosensitiveassembly and the second sub-lens assembly is adjusted according to anembodiment of the present invention.

FIG. 13 illustrates a camera module formed after a connecting step isperformed according to an embodiment of the present invention.

FIG. 14 illustrates an example of targets setting according to anembodiment.

FIG. 15 illustrates a relative position of the first sub-lens assemblyand the second sub-lens assembly after adjustment in step 320 accordingto an embodiment of the present invention.

FIG. 16 is a schematic diagram of further adjusting an angle of an axisof the photosensitive assembly with respect to a central axis of thesecond sub-lens assembly on the basis of FIG. 15 according to anembodiment of the present invention.

FIG. 17 illustrates a camera module formed after a connecting step isperformed on the basis of FIG. 16.

FIG. 18 illustrates an assembled camera module having a motor accordingto an embodiment of the present invention, where the motor is in offstate.

FIG. 19 illustrates an assembled camera module having a motor accordingto an embodiment of the present invention, where the motor is in onstate.

DETAILED DESCRIPTION OF EMBODIMENTS

To facilitate the understanding of the present application, variousaspects of the present application will be described in further detailwith reference to the accompanying drawings. It should be understoodthat these detailed descriptions merely describe exemplaryimplementations of the present application, and are not intended tolimit the scope of the present application in any way. Throughout thisspecification, same reference numerals denote same parts. The term“and/or” includes any and all combinations of one or more of theassociated listed items.

It should be noted that in this specification, the terms such as “first”and “second” are merely used for distinguishing one feature fromanother, and are not intended to impose any limitation on the features.Therefore, a first subject discussed below may also be referred to asecond subject without departing from the teaching of the presentapplication.

In the accompanying drawings, for the convenience of illustration, thethicknesses, sizes, and shapes of objects are slightly exaggerated. Theaccompanying drawings are illustrative only and are not drawn strictlyto scale.

It will be further understood that the terms “comprises,” “comprising,”“having,”“includes,” and/or “including,” when used in thisspecification, specify the presence of stated features, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, steps, operations,elements, components, and/or groups thereof. In addition, expressionssuch as “at least one of,” when preceding a list of elements, modify theentire list of features, rather than individual elements in the list.Moreover, when the implementations of the present application aredescribed, the term “may” is used to indicate “one or moreimplementations of the present application”. Furthermore, the term“exemplary” is used to refer to illustrative description or descriptionby way of example.

As used herein, the terms “substantially”, “about”, and similar termsare used as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be identified by those of ordinary skill inthe art.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by thoseof ordinary skill in the art to which the present application belongs.It will be further understood that terms, such as those defined incommonly used dictionaries, should be interpreted as having a meaningconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

It should be noted that the embodiments of the present application andthe features in the embodiments may be combined with each other on anon-conflict basis. The present application will be described below indetail with reference to the accompanying drawings and in combinationwith the embodiments.

FIG. 1 is a flow chart of a method for assembling a camera moduleaccording to an embodiment of the present invention. Referring to FIG.1, the method includes steps 100 to 500.

In step 100, a first sub-lens assembly, a second sub-lens assembly, anda photosensitive assembly are prepared. FIG. 2 is a schematic diagramillustrating a first sub-lens assembly 1000, a second sub-lens assembly2000, a photosensitive assembly 3000 and their initial positionsaccording to an embodiment of the present invention. Referring to FIG.2, the first sub-lens assembly 1000 includes a first lens barrel 1100and at least one first lens 1200. In this embodiment, the number of thefirst lenses 1200 is two. However, it should be readily understood thatin other embodiments, the number of the first lenses 1200 may also haveother values, for example, one, three, or four.

The second sub-lens assembly 2000 includes a second lens barrel 2100 andat least one second lens 2200. In this embodiment, the number of thesecond lenses 2200 is three. However, it should be readily understoodthat in other embodiments, the number of the second lenses 2200 may alsohave other values, for example, one, two, or four. In this embodiment,the second lens barrel 2100 of the second sub-lens assembly 2000includes an inner lens barrel 2110 and an outer lens barrel 2120 (wherethe outer lens barrel 2120 may also be referred to as a lens base)nested together. The inner lens barrel 2110 and the outer lens barrel2120 are threadedly connected. It should be noted that the threadedconnection is not the only way for connecting the inner lens barrel andthe outer lens barrel. Definitely, it should be readily understood thatin other embodiments, the second lens barrel 2100 may be an integrallens barrel.

Still referring to FIG. 2, in an embodiment, the photosensitive assembly3000 includes a circuit board 3100, a photosensitive element 3200mounted on the circuit board 3100, a tubular support 3400 fabricated onthe circuit board 3100 and surrounding the photosensitive element 3200,and a filter element 3300 mounted on the support 3400. The tubularsupport 3400 has an extension portion that extends inward (toward thephotosensitive element 3200) and that can serve as a lens bracket, andthe filter element 3300 is mounted on the extension portion. The tubularsupport 3400 further has an upper surface, and the photosensitiveassembly may be connected to other components (for example, the secondsub-lens assembly 2000) of the camera module via the upper surface.Definitely, it should be readily understood that in other embodiments,the photosensitive assembly 3000 may be of other structures. Forexample, the circuit board of the photosensitive assembly has a throughhole, and the photosensitive element is mounted in the through hole ofthe circuit board. For another example, a supporting portion is formedaround the photosensitive element by molding, and extends inward to comeinto contact with the photosensitive element (for example, thesupporting portion covers at least one part of a non-photosensitive areathat is located at an edge of the photosensitive element). For stillanother example, the photosensitive assembly may not include the filterelement.

In step 200, the first sub-lens assembly 1000 and the photosensitiveassembly 3000 are arranged on an optical axis of the second sub-lensassembly 2000 to form an optical system capable of imaging and includingthe at least one first lens 1200 and the at least one second lens 2200.In this step, arranging the first sub-lens assembly 1000 and thephotosensitive assembly 3000 on the optical axis of the second sub-lensassembly 2000 means preliminarily aligning (for example, mechanicallyaligning) the three, to form an optical system capable of imaging. Thatis to say, as long as the optical system including all the first lenses1200 and all the second lenses 2200 is capable of imaging, it may beconsidered that the arrangement work in this step is complete. It shouldbe noted that due to various fabrication tolerances of the sub-lensassembly and the photosensitive assembly during fabrication or otherreasons, the central axes of the first lens barrel 1100, the second lensbarrel 2100, and the tubular support 3400 may not coincide with theoptical axis after the arrangement is completed.

In step 300, a relative position of the first sub-lens assembly 1000with respect to the second sub-lens assembly 2000 is adjusted, so as tomaximize an actual measured resolution of imaging of the optical system(where when the actual measured resolution is increased to a presetthreshold, it may be considered that the actual measured resolution ismaximized). The adjustment of the relative position of the firstsub-lens assembly 1000 and the second sub-lens assembly 2000 may beperformed over multiple degrees of freedom.

FIG. 3 illustrates a relative position adjustment method according to anembodiment of the present invention. According to this adjustmentmethod, the first sub-lens assembly 1000 may be moved with respect tothe second sub-lens assembly 2000 in directions x, y, and z (that is,the adjustment of relative position in this embodiment can be performedin three degrees of freedom). The direction z is a direction along theoptical axis, and the directions x and y are directions perpendicular tothe optical axis. The directions x and y are both located in anadjustment plane P, and translation in the adjustment plane P can bedecomposed into two components in the directions x and y.

FIG. 4 illustrates a rotational adjustment according to anotherembodiment of the present invention. In this embodiment, the adjustmentof the relative position can be not only performed in the three degreesof freedom shown in FIG. 3, but also performed in a rotational degree offreedom, that is, adjustment in a direction r. In this embodiment, theadjustment in the direction r is rotation in the adjustment plane P,that is, rotation about an axis perpendicular to the adjustment plane P.

Further, FIG. 5 illustrates a relative position adjustment methodfurther allowing for adjustment in directions v and w according to stillanother embodiment of the present invention. In FIG. 5, the direction vrepresents an angle of rotation in the xoz plane, the direction wrepresents an angle of rotation in the yoz plane, and the angles ofrotation in the direction v and the direction w may form a vector angle,which represents the overall inclination state. That is to say, theinclination posture of the first sub-lens assembly with respect to thesecond sub-lens assembly (that is, the inclination of the optical axisof the first sub-lens assembly with respect to the optical axis of thesecond sub-lens assembly) may be adjusted by adjustment in the directionv and the direction w.

Adjustment over the above-mentioned six degrees of freedom in thedirections x, y, z, r, v, and w may all affect the imaging quality ofthe optical system (for example, the value of the resolution). In otherembodiments of the present invention, the method for adjusting therelative position may be performed in any one of, or any two or more ofthe above-mentioned six degrees of freedom.

Further, in an embodiment, a method for obtaining the actual measuredresolution of imaging of the optical system includes steps 301 and 302.

In step 301, a plurality of targets corresponding to a referencearea/field of view and/or a test area/field of view is set. For example,a center field may be selected as the reference area/field of view, andone or more fields corresponding to a region of interest may be selectedas the test area/field of view (for example, 80% field).

In step 302, the photosensitive assembly is moved along the optical axis(that is, in the direction z), and a resolution defocusing curvecorresponding to each target is acquired based an image output by thephotosensitive assembly. According to the resolution defocusing curve,actual measured resolution of the corresponding field can be obtained.It should be noted that in other embodiments, resolution defocusingcurves corresponding to different test positions in the test area/fieldof view may be obtained by arranging multiple layers of object targets.In this case, in the acquiring of the resolution defocusing curve, thephotosensitive assembly may not need to be moved along the optical axis,or the number of times of moving the photosensitive assembly along theoptical axis may be reduced.

In the above-mentioned embodiment, the resolution may be represented bya modulation transfer function (MTF). A larger MTF value indicateshigher resolution. In this way, according to the MTF defocusing curveacquired based on the image output by the photosensitive assembly, theimaging resolution of the optical system can be obtained in real time.According to the variation of the MTF defocusing curve, it can bedetermined whether a maximum resolution has been reached currently. Whenthe maximum resolution is reached, the relative position adjustment isstopped. FIG. 6 illustrates MTF defocusing curves in an initial stateaccording to an embodiment of the present invention, including an MTFdefocusing curve of the center field and MTF defocusing curves of twotargets corresponding to two different test positions in the testarea/field of view in a sagittal direction and a meridian direction.FIG. 7 illustrates MTF defocusing curves after adjustment in step 300according to an embodiment of the present invention. It can be seen thatafter the adjustment, MTF values of the two targets in the sagittaldirection and the meridian direction both increase obviously. The MTFvalue is not the only parameter for representing the resolution. Forexample, in other embodiments, the resolution may be represented by aspatial frequency response (SFR) or other indicators representing theimaging quality.

After step 300 is completed, there is generally an offset between thefirst sub-lens assembly 1000 and the second sub-lens assembly 2000. FIG.8 illustrates the first sub-lens assembly 1000, the second sub-lensassembly 2000, and the photosensitive assembly 3000 and a positionalrelationship thereof after the relative position of the first sub-lensassembly 1000 and the second sub-lens assembly 2000 are adjustedaccording to an embodiment of the present invention. It can be seen thatthe central axis of the first sub-lens assembly 1000 is offset withrespect to the central axis of the second sub-lens assembly 2000 in thedirection x by Δx. It should be noted that FIG. 8 is merely exemplary.Although no offset in the direction y is shown in FIG. 8, it should bereadily understood by those skilled in the art that the central axis ofthe first sub-lens assembly 1000 may also be offset with respect to thecentral axis of the second sub-lens assembly 2000 in the direction y byΔy.

In step 400, an angle of an axis of the photosensitive assembly 3000with respect to the central axis of the second sub-lens assembly 2000 isadjusted, so as to minimize an actual measured image plane inclinationof imaging of the optical system obtained by using the photosensitiveelement (where when the actual measured image plane inclination isdecreased to a preset threshold, it may be considered that the actualmeasured image plane inclination is minimized). Due to the inherenttolerance of the optical assembly fabrication process, and theadjustment of the optical system in step 300, an image plane inclinationoften occurs during imaging of the optical system. FIG. 9 is a schematicprinciple diagram of an image plane inclination. It can be seen that inFIG. 9, an object plane perpendicular to the optical axis forms aninclined image plane after lens imaging. Incident light of the centerfield is focused at a central focus after passing through a lens.Incident light of an off-axis area/field of view 1 is focused at aperipheral focus 1′ after passing through the lens, where there is anaxial deviation D2 between the peripheral focus 1′ and the centralfocus. Incident light of an off-axis area/field of view 1′ is focused ata peripheral focus 1 after passing through the lens, where there is anaxial deviation D1 between the peripheral focus 1 and the central focus.As a result, when the receiving surface of the photosensitive element isdisposed perpendicularly to the optical axis, clear imaging cannot beachieved at the periphery 1 and the periphery 1′. FIG. 10 is a schematicdiagram of comparison of images at the central position, the periphery1, and the periphery 1′. It can be seen that images at the periphery 1and the periphery 1′ are obviously more blurred than the image at thecentral position.

In this step, the angle of the axis of the photosensitive assembly 3000with respect to the central axis of the second sub-lens assembly 2000 isadjusted to compensate for the above-mentioned image plane inclination,so as to improve the imaging quality of the camera module product. In anembodiment, a method for acquiring the actual measured image planeinclination includes steps 401 and 402.

In step 401, for any test area/field of view (for example, 80% field), aplurality of targets corresponding to different test positions in thetest area/field of view is set. Herein, the different test positionsrefer to a plurality of test positions of a same test area/field of viewin a plurality of different directions.

In step 402, a resolution defocusing curve corresponding to each targetof a same field is acquired based on an image output by thephotosensitive assembly. When the resolution defocusing curves convergeon the abscissa axis (the coordinate axis representing a defocusingamount), it indicates that the image plane inclination corresponding tothe test area/field of view has been compensated for, that is, theminimization of the actual measured image plane inclination has beenachieved in the test area/field of view. In this step, the term“converge” may be construed as that: position offsets of peaks ofresolution defocusing curves corresponding to a plurality of targets ofa same field on the abscissa axis (representing a position offset alongthe optical axis direction) are less than a preset threshold.

FIG. 11 illustrates MTF defocusing curves after adjustment in step 400according to an embodiment of the present invention. After step 400 iscompleted, the axis of the photosensitive assembly 3000 often has anangle of inclination with respect to the central axis of the secondsub-lens assembly 2000. FIG. 12 illustrates the first sub-lens assembly1000, the second sub-lens assembly 2000, and the photosensitive assembly3000 and a positional relationship thereof after the relativeinclination between the photosensitive assembly 3000 and the secondsub-lens assembly 2000 is adjusted according to an embodiment of thepresent invention. It can be seen that the axis of the photosensitiveassembly 3000 has an angle of inclination Δv in the direction v withrespect to the central axis of the second sub-lens assembly 2000.Although no inclination in the direction w is shown in FIG. 12, itshould be readily understood by those skilled in the art that the axisof the photosensitive assembly 3000 may also have an angle ofinclination in the direction w with respect to the central axis of thesecond sub-lens assembly 2000.

In step 500, the first sub-lens assembly 1000 and the second sub-lensassembly 2000 are connected, so that the relative position of the firstsub-lens assembly 1000 and the second sub-lens assembly 2000 remainunchanged; and the photosensitive assembly 3000 and the second sub-lensassembly 2000 are connected, so that the angle of the axis of thephotosensitive assembly 3000 with respect to the central axis of thesecond sub-lens assembly 2000 remains unchanged. FIG. 13 illustrates acamera module formed after a connecting step is performed according toan embodiment of the present invention.

The process for connecting the first sub-lens assembly and the secondsub-lens assembly may be selected as required. For example, in anembodiment, the first sub-lens assembly and the second sub-lens assemblyare connected by a bonding process. As shown in FIG. 13, in thisembodiment, the first sub-lens assembly 1000 and the second sub-lensassembly 2000 are bonded by using an adhesive material 4000, and thesecond sub-lens assembly 2000 and the photosensitive assembly 3000 arebonded by using an adhesive material 5000. In another embodiment, thefirst sub-lens assembly and the second sub-lens assembly are connectedby a laser welding process. In still another embodiment, the firstsub-lens assembly and the second sub-lens assembly are connected by anultrasonic welding process. In addition to the above-mentionedprocesses, other welding processes may also be used. It should be notedthat in the present invention, the term “connection” is not limited todirect connection. For example, in an embodiment, the first sub-lensassembly and the second sub-lens assembly may be connected via anintermediate member (which maybe rigid). Such connection via anintermediate member falls within the meaning of the term “connection” aslong as the relative position of (including relative distance andposture) of the first sub-lens assembly and the second sub-lens assembly(or the photosensitive assembly and the second sub-lens assembly) remainunchanged.

The method for assembling a camera module according to theabove-mentioned embodiment can improve the resolution of the cameramodule and the capability of process index (CPK) of mass production ofthe camera module; can lower the requirements on the material precisionand assembly precision of various elements of the optical imaging lensassembly and module, and reduce the overall costs of the optical imaginglens assembly and module. The method can implement a real-timeadjustment of various aberrations of the camera module during theassembly process to reduce the fluctuation of the imaging quality,thereby reducing the failure rate and the production costs, andimproving the imaging quality.

In addition, in the above-mentioned embodiment, the relative position ofthe first sub-lens assembly and the second sub-lens assembly can beadjusted with multiple degrees of freedom during the assembly process toimprove the resolution, and the image plane inclination caused by theadjustment of the relative position of the first sub-lens assembly andthe second sub-lens assembly can be compensated for by adjusting therelative inclination between the photosensitive assembly and the secondsub-lens assembly, thereby further improving the imaging quality.Because the influence of the adjustment of relative position on theimage plane inclination does not need to be considered or does not needto be considered too much during the adjustment of the relative positionof the first sub-lens assembly and the second sub-lens assembly, theassembly efficiency can also be increased effectively.

Further, in an embodiment, in step 400, targets are set in pair for theselected test area/field of view. For example, a pair of first targetsrespectively located at two ends of the central position are set in afirst direction, and a pair of second targets respectively located attwo ends of the central position are set in a second direction. FIG. 14illustrates an example of a target setting according to an embodiment.As shown in FIG. 14, the test area/field of view is 80% field, and thefour targets are respectively disposed at four corners of a chart. Thelower left target and the upper right target may be used as the pair offirst targets in the first direction, and the upper left target and thelower right target may be used as the pair of second targets in thesecond direction. An inclination component of the actual measured imageplane of imaging of the optical system in the first direction can beidentified according to an offset vector of a resolution defocusingcurve of the pair of first targets in the abscissa axis direction, andan inclination component of the actual measured image plane of imagingof the optical system in the second direction can be identifiedaccording to an offset vector of a resolution defocusing curve of thepair of second targets in the abscissa axis direction. Then, the postureof the photosensitive assembly is adjusted to change the angle of theaxis of the photosensitive assembly with respect to the axis of thesecond sub-lens assembly, so as to compensate for the inclinationcomponent in the first direction and the inclination component in thesecond direction.

Further, in an embodiment, step 300 includes steps 310 and 320.

In step 310, the actual measured resolution of imaging of the opticalsystem is increased to a corresponding threshold by moving the firstsub-lens assembly with respect to the second sub-lens assembly in theadjustment plane. The adjustment over six degrees of freedom in thedirections x, y, z, r, v, and w has been described above. Translation inthe directions x and y and rotation in the direction r may be consideredto be movement in the adjustment plane in this step. In this step, aplurality of targets corresponding to the reference area/field of viewand the test area/field of view is set, and then a resolution defocusingcurve corresponding to each target is acquired based on an image outputby the photosensitive assembly. The first sub-lens assembly is movedwith respect to the second sub-lens assembly in the directions x, y, andr, so that a peak of a resolution defocusing curve corresponding toimaging of a target of the reference area/field of view is increased toa corresponding threshold. The center field is usually used as thereference area/field of view. However, it should be noted that thereference area/field of view is not limited to the center field. In someembodiments, other fields may also be selected as the referencearea/field of view. In this step, increasing the actual measuredresolution to a corresponding threshold is: increasing a peak of aresolution defocusing curve corresponding to imaging of a target of thereference area/field of view to a corresponding threshold.

Still referring to FIG. 8, in an embodiment of the present invention,after the adjustment in step 310, the central axis of the first sub-lensassembly is offset with respect to the central axis of the secondsub-lens assembly in the direction x by Δx.

In step 320, the actual measured resolution of imaging of the opticalsystem in the test area/field of view is increased to a correspondingthreshold by tilting the axis of the first sub-lens assembly withrespect to the axis of the second sub-lens assembly. Rotation in thedirections v and w corresponds to the tilting adjustment in this step.In this step, increasing the actual measured resolution to acorresponding threshold includes: increasing the smallest one of peaksof resolution defocusing curves corresponding to imaging of a pluralityof targets in the test area/field of view to a corresponding threshold.In other embodiments, increasing the actual measured resolution to acorresponding threshold may further include: increasing uniformity ofthe peaks of the resolution defocusing curves corresponding to imagingof the plurality of targets in the test area/field of view to acorresponding threshold. Increasing the uniformity of the peaksincludes: decreasing a variance of the peaks of the resolutiondefocusing curves corresponding to imaging of the plurality of targetsin the test area/field of view to a corresponding threshold. FIG. 15illustrates the relative position of the first sub-lens assembly and thesecond sub-lens assembly after adjustment in step 320 according to anembodiment of the present invention. It can be seen that in FIG. 15, thecentral axis of the first sub-lens assembly is offset with respect tothe central axis of the second sub-lens assembly in the direction x byΔx, and the central axis of the first sub-lens assembly is also inclinedwith respect to the central axis of the second sub-lens assembly by Δv2.Although no inclination in the direction w is shown in FIG. 15, itshould be readily understood by those skilled in the art that thecentral axis of the first sub-lens assembly may also have an angle ofinclination with respect to the central axis of the second sub-lensassembly in the direction w.

Further, FIG. 16 is a schematic diagram of further adjusting the angleof the axis of the photosensitive assembly with respect to the centralaxis of the second sub-lens assembly on the basis of FIG. 15 accordingto an embodiment of the present invention. It can be seen that in FIG.16, the axis of the photosensitive assembly has an angle Δv3 withrespect to the central axis of the second sub-lens assembly. FIG. 17illustrates a camera module formed after a connecting step is performedon the basis of FIG. 16. This embodiment can improve the assemblyefficiency and the imaging quality of the camera module.

Further, in an embodiment, step 300 may further include: matching anactual measured image plane of imaging of the optical system with atarget surface by moving the first sub-lens assembly with respect to thesecond sub-lens assembly in the optical axis direction. The adjustmentover six degrees of freedom in the directions x, y, z, r, v, and w hasbeen described above. Movement in the direction z may be considered tobe movement in the optical axis direction in this step.

After the optical lens assembly is assembled, an expected imagingsurface will be obtained. Herein, the expected imaging surface isreferred to as the target surface. In some cases, the target surface isa plane. For example, to achieve optimal imaging quality, if thephotosensitive surface of the photosensitive element of the cameramodule corresponding to the optical lens assembly is a plane, theexpected imaging surface of the optical lens assembly is also a plane.That is to say, the target surface is a plane. In some other cases, thetarget surface may be a convex or concave curved surface, or acorrugated curved surface. For example, to achieve optimal imagingquality, if the photosensitive surface of the photosensitive element ofthe camera module corresponding to the optical lens assembly is a convexor concave curved surface, the target surface should also be a convex orconcave curved surface; if the photosensitive surface of thephotosensitive element of the camera module corresponding to the opticallens assembly is a corrugated curved surface, the target surface shouldalso be a corrugated curved surface.

In an embodiment, it is identified according to an image output by thephotosensitive element whether the actual measured image plane matchesthe target surface. In the matching the actual measured image plane withthe target surface, matching the actual measured image plane with thetarget surface includes: obtaining an actual measured field curvature ofthe module according to the image output by the photosensitive element,and causing the actual measured field curvature of the module to fallwithin a range of +/−5 μm. This embodiment can further improve theimaging quality of the camera module.

Further, in an embodiment, the imaging quality of the camera module isfurther improved by introducing a readjustment step. In this embodiment,in step 300, the first sub-lens assembly is moved with respect to thesecond sub-lens assembly within a first range in the adjustment plane.

In step 400, if the actual measured image plane inclination cannot bedecreased to fall within a preset range, a readjustment step 410 isfurther performed until the actual measured image plane inclination isdecreased to fall within the preset range.

The readjustment step 410 includes steps 411 and 412.

In step 411, the first sub-lens assembly is moved with respect to thesecond sub-lens assembly within a second range in the adjustment plane.The second range is smaller than the first range. That is to say,compared with step 300, in step 411, the relative position of the firstsub-lens assembly and the second sub-lens assembly are adjusted within asmall range in the adjustment plane. On one hand, because the adjustmentrange is small, the actual measured resolution achieved after theadjustment in step 300 can basically be maintained. On the other hand,the image plane inclination can be reduced, making it easier tocompensate for the image plane inclination in step 412.

In step 412, the angle of the axis of the photosensitive assembly withrespect to the axis of the second sub-lens assembly is adjusted, so thatan actual measured image plane inclination of imaging of the opticalsystem, obtained by using the photosensitive element, is decreased to acorresponding threshold.

According to an embodiment of the present invention, a camera moduleobtained by the above-mentioned method for assembling a camera module isfurther provided. Referring to FIG. 17, the camera module includes: afirst sub-lens assembly 1000, including a first lens barrel 1100 and atleast one first lens 1200; a second sub-lens assembly 2000, including asecond lens barrel 2100 and at least one second lens 2200; and aphotosensitive assembly 3000, including a photosensitive element 3200.

The first sub-lens assembly 1000 and the photosensitive assembly 3000are arranged on an optical axis of the second sub-lens assembly 2000 toform an optical system capable of imaging and including the at least onefirst lens 1200 and the at least one second lens 2200. The firstsub-lens assembly 1000 and the second sub-lens assembly 2000 are fixedtogether by a first connecting medium 4000, so that the relativeposition of the first sub-lens assembly 1000 and the second sub-lensassembly 2000 remain unchanged, and the relative position cause actualmeasured resolution of imaging of the optical system to be increased toa first threshold. The second sub-lens assembly 2000 and thephotosensitive assembly 3000 are fixed together by a second connectingmedium 5000, so that an angle between a central axis of the secondsub-lens assembly 2000 and an axis of the photosensitive element 3000remains unchanged, and so that an actual measured image planeinclination of imaging of the optical system, obtained by using thephotosensitive element 3200, is decreased to a second threshold.

In an embodiment, the first connecting medium may be an adhesivematerial or a bonding pad (for example, a metal sheet). The secondconnecting medium may be an adhesive material or a bonding pad (forexample, a metal sheet). The first connecting medium by which the firstsub-lens assembly and the second sub-lens assembly are connected andfixed together is neither part of the first sub-lens assembly, nor partof the second sub-lens assembly. The second connecting medium by whichthe second sub-lens assembly and the photosensitive assembly areconnected and fixed together is neither part of the second sub-lensassembly, nor part of the photosensitive assembly.

Further, in an embodiment, the first connecting medium is adapted toprevent the first sub-lens assembly and the second sub-lens assemblyfrom abutting against each other. A structural clearance exists betweenthe first sub-lens assembly and the second sub-lens assembly, and thefirst sub-lens assembly and the second sub-lens assembly both have anoptical surface and a structural surface. In the lens assembly, theoptical surface is a surface, through which effective light passes, on alens. Other surfaces on the lens than the optical surface are thestructural surfaces. Surfaces located on the lens barrel are allstructural surfaces. The structural clearance is a clearance betweenstructural surfaces.

Further, in an embodiment, a central axis of the first sub-lens assemblyis staggered with respect to the central axis of the second sub-lensassembly by 0 to 15 μm.

Further, in an embodiment, a central axis of the first sub-lens assemblyhas an angle of inclination of smaller than 0.5° with respect to thecentral axis of the second sub-lens assembly.

Further, in an embodiment, the central axis of the second sub-lensassembly has an angle of inclination of smaller than 1° with respect tothe axis of the photosensitive assembly.

The central axis of the first sub-lens assembly and the central axis ofthe second sub-lens assembly are mentioned multiple times herein.Referring to FIG. 17, for the convenience of measurement, the centralaxis of the first sub-lens assembly may be construed as a central axisof an optical surface 1201, which is closest to the second sub-lensassembly 2000, in the first sub-lens assembly 1000; or may be construedas a central axis defined by a structural surface 1202 of the first lens1200 that is closest to the second sub-lens assembly 2000. When thefirst lens 1200 and the first lens barrel 1100 of the first sub-lensassembly 1000 are tightly assembled, the central axis of the firstsub-lens assembly 1000 may also be construed as a central axis definedby an inner side surface 1101 of the first lens barrel.

Similarly, for the convenience of measurement, the central axis of thesecond sub-lens assembly 2000 may be construed as a central axis of anoptical surface 2201, which is closest to the first sub-lens assembly1000, in the second sub-lens assembly 2000; or may be construed as acentral axis defined by a structural surface 2202 of the second lens2200 that is closest to the first sub-lens assembly 1000. When thesecond lens 2200 and the second lens barrel 2100 of the second sub-lensassembly 2000 are tightly assembled, the central axis of the secondsub-lens assembly 2000 may also be construed as a central axis definedby an inner side surface 2101 of the second lens barrel.

Similarly, for the convenience of measurement, the axis of thephotosensitive assembly 3000 may be construed as a central axis definedby an inner side surface of the tubular support 3400 of thephotosensitive assembly 3000; or may be construed as a normal line of alight incident surface of the photosensitive assembly 3000. When thephotosensitive assembly 3000 has a filter element, the axis of thephotosensitive assembly 3000 may also be construed as an axis of thefilter element 3300.

The present invention is particularly suitable for a miniature cameramodule that is applied to a smart terminal and that includes a lensassembly having a diameter of less than 10 mm. In an embodiment, outerside surfaces of the first sub-lens assembly and the second sub-lensassembly both provide a sufficient contact surface, so that a mechanicalarm (or other pick-up apparatus) can pick up (for example, clamp orsuck) the first sub-lens assembly and the second sub-lens assembly viathe contact surface, thereby implementing the precise adjustment of therelative position of the first sub-lens assembly and the second sub-lensassembly. Such precise adjustment may be adjustment in six degrees offreedom. The adjustment step may reach the micron order or a moreprecise level.

Further, in an embodiment, the second sub-lens assembly 2000 may furtherinclude a motor, so as to achieve autofocusing of a camera module of amobile phone. FIG. 18 illustrates an assembled camera module having amotor according to an embodiment of the present invention, where themotor is in off state. FIG. 19 illustrates an assembled camera modulehaving a motor according to an embodiment of the present invention,where the motor is in on state. In this embodiment, the motor includes amotor base 2310 and a motor support 2320 mounted on the motor base 2310.The motor support 2320 surrounds the second lens barrel 2100, and adriving structure (not shown) of the motor is mounted on the motorsupport 2320. The motor support 2320 is connected to the second lensbarrel 2100 by a reed 2330. When the driving structure is electrified,the second lens barrel moves along the optical axis, and the reed 2330deforms (as shown in FIG. 19). In step 300 and step 400, the motor, thesecond lens barrel 2100, and the second lens 2200 mounted in the secondlens barrel 2100 are moved and adjusted as the whole second sub-lensassembly 2000. In step 500, the motor base 2310 and the photosensitiveassembly 3000 are connected so as to achieve the connection between thesecond sub-lens assembly 2000 and the photosensitive assembly 3000.Further, in step 300, when the relative position of the first sub-lensassembly and the second sub-lens assembly are adjusted, the motor ismaintained in on state (for example, the motor being electrified may beconsidered to indicate that the motor is started). In this way, theactual measured resolution acquired is actual measured resolutionobtained when the motor is in on state. In step 400, when the angle ofinclination of the photosensitive assembly with respect to the centralaxis of the second sub-lens assembly is adjusted, the motor is alsomaintained in on state. In this way, the actual measured image planeinclination acquired is an actual measured image plane inclinationobtained when the motor is in on state. After the motor is started, thereed deforms correspondingly. However, compared with the case where themotor is in off state, the deformation of the reed due to starting ofthe motor may lead to an additional inclination of the central axis ofthe second lens barrel with respect to the central axis of the firstsub-lens assembly (referring to the angle of inclination Δv4 in FIG.19). In the solution of this embodiment, the additional inclination ofthe second lens barrel caused by starting of the motor can becompensated for during the adjustment in step 300 and step 400, therebyfurther improving the imaging quality of the autofocus camera module.

The foregoing is only a description of the preferred implementations ofthe present application and the applied technical principles. It shouldbe appreciated by those skilled in the art that the inventive scope ofthe present application is not limited to the technical solutions formedby the particular combinations of the above technical features. Theinventive scope should also cover other technical solutions formed byany combinations of the above technical features or equivalent featuresthereof without departing from the concept of the invention, such as,technical solutions formed by replacing the features as disclosed in thepresent application with (but not limited to), technical features withsimilar functions.

What is claimed is:
 1. A method for assembling a camera module, themethod comprising: preparing a first sub-lens assembly, a secondsub-lens assembly, and a photosensitive assembly, wherein the firstsub-lens assembly comprises a first lens barrel and at least one firstlens, the second sub-lens assembly comprises a second lens barrel and atleast one second lens, and the photosensitive assembly comprises aphotosensitive element; arranging the first sub-lens assembly and thephotosensitive assembly on an optical axis of the second sub-lensassembly, to form an optical system capable of imaging and comprisingthe at least one first lens and the at least one second lens; increasingan actual measured resolution of imaging of the optical system to afirst threshold by adjusting a relative position of the first sub-lensassembly with respect to the second sub-lens assembly; decreasing anactual measured image plane inclination of imaging of the opticalsystem, obtained by using the photosensitive element, to a secondthreshold by adjusting an angle of an axis of the photosensitiveassembly with respect to a central axis of the second sub-lens assembly;and connecting the first sub-lens assembly and the second sub-lensassembly, so that the relative position of the first sub-lens assemblyand the second sub-lens assembly remain unchanged; and connecting thephotosensitive assembly and the second sub-lens assembly, so that theangle of the axis of the photosensitive assembly with respect to thecentral axis of the second sub-lens assembly remains unchanged.
 2. Themethod for assembling a camera module according to claim 1, wherein inthe increasing actual measured resolution of imaging of the opticalsystem to the first threshold, the adjusting the relative positioncomprises: increasing the actual measured resolution of imaging of theoptical system by moving the first sub-lens assembly with respect to thesecond sub-lens assembly in an adjustment plane.
 3. The method forassembling a camera module according to claim 2, wherein in theincreasing actual measured resolution of imaging of the optical systemto the first threshold, the movement in the adjustment plane comprisestranslation and/or rotation in the adjustment plane.
 4. The method forassembling a camera module according to claim 1, wherein the decreasingthe actual measured image plane inclination of imaging of the opticalsystem, obtained by using the photosensitive element, to the secondthreshold is performed after the increasing actual measured resolutionof imaging of the optical system to the first threshold.
 5. The methodfor assembling a camera module according to claim 1, wherein in thedecreasing the actual measured image plane inclination of imaging of theoptical system, obtained by using the photosensitive element, to thesecond threshold, obtaining the actual measured image plane inclinationcomprises: setting a plurality of targets corresponding to differenttest points in a test area/field of view; and acquiring a resolutiondefocusing curve corresponding to each test point based on an imageoutput by the photosensitive assembly.
 6. The method for assembling acamera module according to claim 5, wherein in the decreasing the actualmeasured image plane inclination of imaging of the optical system,obtained by using the photosensitive element, to the second threshold,the decreasing the actual measured image plane inclination to the secondthreshold is: decreasing a position offset in the optical axis directionbetween peaks of the resolution defocusing curves corresponding to thedifferent test points in the test area/field of view to the secondthreshold.
 7. The method for assembling a camera module according toclaim 1, wherein the increasing actual measured resolution of imaging ofthe optical system to the first threshold comprises: increasing actualmeasured resolution of imaging of the optical system in a referencearea/field of view to a corresponding threshold by moving the firstsub-lens assembly with respect to the second sub-lens assembly in anadjustment plane; and then increasing actual measured resolution ofimaging of the optical system in a test area/field of view to acorresponding threshold by tilting a central axis of the first sub-lensassembly with respect to a central axis of the second sub-lens assembly.8. The method for assembling a camera module according to claim 7,wherein in the increasing actual measured resolution of imaging of theoptical system to the first threshold, obtaining the actual measuredresolution of imaging of the optical system comprises: setting aplurality of targets corresponding to different test points in thereference area/field of view and the test area/field of view; andacquiring a resolution defocusing curve corresponding to each test pointbased on an image output by the photosensitive assembly.
 9. The methodfor assembling a camera module according to claim 7, wherein in theincreasing actual measured resolution of imaging of the optical systemin the reference area/field of view to the corresponding threshold, theincreasing the actual measured resolution to the corresponding thresholdcomprises: increasing a peak of a resolution defocusing curvecorresponding to imaging of a target of a test point in the referencearea/field of view to the corresponding threshold.
 10. The method forassembling a camera module according to claim 7, wherein in theincreasing actual measured resolution of imaging of the optical systemin the test area/field of view to the corresponding threshold, theincreasing the actual measured resolution to the corresponding thresholdcomprises: increasing a smallest one of peaks of resolution defocusingcurves corresponding to imaging of a plurality of targets in the testarea/field of view to the corresponding threshold.
 11. The method forassembling a camera module according to claim 1, wherein the increasingactual measured resolution of imaging of the optical system to the firstthreshold further comprises: matching an actual measured image plane ofimaging of the optical system obtained according to an image output bythe photosensitive element with a target surface by moving the firstsub-lens assembly with respect to the second sub-lens assembly along theoptical axis.
 12. The method for assembling a camera module according toclaim 1, wherein in the increasing the actual measured resolution ofimaging of the optical system to the first threshold, the first sub-lensassembly is moved with respect to the second sub-lens assembly within afirst range in an adjustment plane; and in the decreasing the actualmeasured image plane inclination of imaging of the optical system,obtained by using the photosensitive element, to the second threshold,if the actual measured image plane inclination cannot reach the secondthreshold, a readjustment step is further performed until the actualmeasured image plane inclination is decreased to the second threshold,wherein the readjustment step comprises: moving the first sub-lensassembly with respect to the second sub-lens assembly within a secondrange in the adjustment plane, wherein the second range is smaller thanthe first range; and adjusting an angle of the axis of thephotosensitive assembly with respect to the optical axis, so as todecrease the actual measured image plane inclination of imaging of theoptical system obtained by using the photosensitive element.
 13. Themethod for assembling a camera module according to claim 1, wherein inthe connecting, the first sub-lens assembly and the second sub-lensassembly are connected by a bonding or welding process.
 14. The methodfor assembling a camera module according to claim 1, wherein in theconnecting, the photosensitive assembly and the second sub-lens assemblyare connected by a bonding or welding process.
 15. The method forassembling a camera module according to claim 14, wherein the weldingprocess comprises laser welding or ultrasonic welding.
 16. A cameramodule, comprising: a first sub-lens assembly, comprising a first lensbarrel and at least one first lens; a second sub-lens assembly,comprising a second lens barrel and at least one second lens; and aphotosensitive assembly, comprising a photosensitive element, whereinthe first sub-lens assembly and the photosensitive assembly are arrangedon an optical axis of the second sub-lens assembly to form an opticalsystem capable of imaging and comprising the at least one first lens andthe at least one second lens; the first sub-lens assembly and the secondsub-lens assembly are fixed together by a first connecting medium; andthe second sub-lens assembly and the photosensitive assembly are fixedtogether by a second connecting medium, wherein the second connectingmedium is adapted to cause a central axis of the second sub-lensassembly to have a second angle of inclination with respect to an axisof the photosensitive assembly.
 17. The camera module according to claim16, wherein the first connecting medium is adapted to prevent the firstsub-lens assembly and the second sub-lens assembly from abutting againsteach other.
 18. The camera module according to claim 16, wherein thefirst connecting medium is further adapted to cause a central axis ofthe first sub-lens assembly to have a first angle of inclination withrespect to the central axis of the second sub-lens assembly.
 19. Thecamera module according to claim 16, wherein the first connecting mediumis further adapted to cause a central axis of the first sub-lensassembly to be staggered with respect to the central axis of the secondsub-lens assembly.
 20. The camera module according to claim 16, whereinthe first connecting medium is further adapted to cause the firstsub-lens assembly and the second sub-lens assembly to have a structuralclearance therebetween.
 21. The camera module according to claim 16,wherein the first connecting medium is a bonding medium or a weldingmedium, and the second connecting medium is a bonding medium or awelding medium.
 22. The camera module according to claim 16, wherein acentral axis of the first sub-lens assembly is staggered with respect tothe central axis of the second sub-lens assembly by 0 to 15 μm.
 23. Thecamera module according to claim 16, wherein a central axis of the firstsub-lens assembly has an angle of inclination of smaller than 0.5° withrespect to the central axis of the second sub-lens assembly.
 24. Thecamera module according to claim 16, wherein the central axis of thesecond sub-lens assembly has an angle of inclination of smaller than 1°with respect to the axis of the photosensitive assembly.
 25. The cameramodule according to claim 16, wherein the first connecting medium isfurther adapted to cause a relative position of the first sub-lensassembly and the second sub-lens assembly to remain unchanged, and therelative position cause actual measured resolution of imaging of theoptical system to be increased to a first threshold; and the secondconnecting medium is further adapted to cause an actual measured imageplane inclination of imaging of the optical system, obtained by usingthe photosensitive element, to be decreased to a second threshold. 26.The camera module according to claim 25, wherein the second sub-lensassembly further comprises a motor, the motor comprises a motor base,and the photosensitive assembly is connected to the motor base by thesecond connecting medium, and wherein the actual measured resolution isobtained when the motor is in on state, and the actual measured imageplane inclination is obtained when the motor is in on state.